High-molecular-weight nonionic PAM is screened where fine particles require extended polymer bridges but strong ionic interaction is not the preferred starting mechanism. Longer chains can improve aggregation while also raising solution viscosity and sensitivity to poor distribution.
Define the solids and separator
Record particle size, mineral or precipitate identity, solids concentration, pH, conductivity and upstream reagents. State whether the duty is clarification, thickening, filtration or fine-particle capture because the best visible floc may not deliver the best separator result.
Use fresh representative feed and include the difficult operating condition. Stored samples may settle selectively or change surface chemistry.
Control preparation and shear
Prepare every candidate at equal active concentration with the same water, wetting method, maturation and age. Verify that no fisheyes or undissolved fragments remain. Dilute the stock sufficiently for even contact without applying destructive shear after floc growth.
Compare a defined shear challenge when transfer pumps, feedwells or mixers are energetic. Large fragile floc can disappear before reaching the separator.
Rank complete performance
Measure settling or filtration response, clear-water quality, final solids volume, compaction, drainage and product consumption. Include underdose and overdose symptoms and calculate delivered treatment cost rather than ranking only product price.
Confirm the finalist in a controlled plant trial before assigning the grade to purchasing.